Benfotiamine derivatives, method for preparing the same and pharmaceutical composition comprising the same

ABSTRACT

The present disclosure relates to benfotiamine derivatives, a method for preparing the same and a pharmaceutical composition, as indicated below, comprising the same. In the present disclosure, when the ortho position of benzene ring is only a halogen atom or an ethoxy substitution, or the meta position is only a bromine 5 atom, a chlorine atom, a fluorine atom or a nitro substitution, or the para position is only a chlorine atom, a methoxy substitution or a nitro substitution, its compound has a significant inhibition effect on Aβ40 and Aβ42. Furthermore, when the ortho position of benzene ring is only a fluorine atom or a bromine atom substitution, the compound has an outstanding inhibition effect on Aβ40 and Aβ42.

TECHNICAL FIELD

The present disclosure relates to the fields of medicine and chemistry,and more particularly, to benfotiamine derivatives, a method forpreparing the same and a pharmaceutical composition comprising the same.

BACKGROUND

Alzheimers disease (AD, commonly known as senile dementia) is aprogressive neurodegenerative disorder characterized by cognitive andbehavioral disorders. It is one of the most common form of elderlydementia primarily with recognition disorder and rapid decay in memoryfunction. The main pathological features of Alzheimer's disease aresenile plaques caused by the deposition of β-amyloid (Aβ) in the brain,neurofibrillary tangles caused by the hyperphosphorylation of tauprotein, the glucose dysmetabolism in the brain and the loss ofneuronal/synaptic junction. Due to long courses of illness and the poorself-care ability of patients, AD brings serious mental and economicburdens to families and the society. However, currently, few medicinesin the worldwide can prevent or slow down the progression of thisdisease. Medicines on the market now for the treatment of AD aresymptomatic, which can only control or improve cognitive and functionalsymptoms for a period of time, but cannot prevent or delay thedeterioration of the disease.

Benfotiamine, chemical name: S-[2-[[(4-amino-2-methyl-5-pyrimidinyl)methyl] formylamino]-1-[2-(phosphonooxy)ethyl]-1-propenyl]ester, themolecular formula: C₉H₂₃N₄O₆PS, which can greatly improvelow-bioavailability of water-soluble vitamin B₁ and can elevate thethiamine level in the blood and tissues, thereby increasing the curativeeffect. The present researches on benfotiamine mainly focus on thesynthesis method, the crystal form and the application in medicine.Although recent studies have shown that benfotiamine can be used to thepreparation of the prevention and treatment of Alzheimer's disease, forexample, the patent application CN200710041571.X discloses apharmaceutical composition containing benfotiamine for the treatment ofAlzheimer's disease, no studies have been found on the use ofbenfotiamine derivatives and medicine uses thereof, particularly thederivatives used in Alzheimer's disease.

SUMMARY

Embodiments of the present disclosure provide benfotiamine derivatives,a method for preparation of the same and a pharmaceutical compositioncomprising the same.

In an embodiment, benfotiamine derivatives are provided, wherein thebenfotiamine derivatives are as shown in formula (1):

wherein, R₁ is selected from a group consisting of hydrogen atom,halogen atom, nitro group, cyano group, sulfo group, amino group,carboxyl group, hydroxyl group, sulfydryl group, hydrocarbyl group,substituted hydrocarbyl group, alkoxy group, substituted alkoxy groupand acyl group;

R₂ is selected from a group consisting of hydrogen atom, halogen atom,nitro group, cyano group, sulfo group, amino group, carboxyl group,hydroxyl group, sulfydryl group, hydrocarbyl group, substitutedhydrocarbyl group, alkoxy group, substituted alkoxy group and acylgroup;

R₃ is selected from a group consisting of hydrogen atom, halogen atom,nitro group, cyano group, sulfo group, amino group, carboxyl group,hydroxyl group, sulfydryl group, hydrocarbyl group, substitutedhydrocarbyl group, alkoxy group, substituted alkoxy group and acylgroup;

R₄ is selected from a group consisting of hydrogen atom, halogen atom,nitro group, cyano group, sulfo group, amino group, carboxyl group,hydroxyl group, sulfydryl group, hydrocarbyl group, substitutedhydrocarbyl group, alkoxy group, substituted alkoxy group and acylgroup;

R₅ is selected from a group consisting of hydrogen atom, halogen atom,nitro group, cyano group, sulfo group, amino group, carboxyl group,hydroxyl group, sulfydryl group, hydrocarbyl group, substitutedhydrocarbyl group, alkoxy group, substituted alkoxy group and acylgroup; and

wherein at least one of R₁, R₂, R₃, R₄ and R₅ is not hydrogen atom.

Optionally, only one of R₁, R₂, R₃, R₄ and R₅ is not hydrogen atom, andany one of the others is hydrogen atom.

Optionally, each one of R₂, R₃, R₄ and R₅ is hydrogen atom, and R₁ ishalogen atom or ethoxy group.

Optionally, each one of R₂, R₃, R₄ and R₅ is hydrogen atom, and R₁ isfluorine atom or bromine atom.

Optionally, each one of R₁, R₃, R₄ and R₅ is hydrogen atom, and R₂ isbromine atom, chlorine atom, fluorine atom or nitro group.

Optionally, each one of R₁, R₂, R₄ and R₅ is hydrogen atom, and R₃ ischlorine atom, methoxy group or nitro group.

In an embodiment, a method for preparing the above benfotiaminederivatives is provided, wherein a compound of monophosphothiamine theformula (1a) shows reacts with a compound of benzoyl chloride theformula (1b) shows so as to prepare and obtain the benfotiaminederivatives of the formula (1).

R₂ is selected from a group consisting of hydrogen atom, halogen atom,nitro group, cyano group, sulfo group, amino group, carboxyl group,hydroxyl group, sulfydryl group, hydrocarbyl group, substitutedhydrocarbyl group, alkoxy group, substituted alkoxy group and acylgroup;

R₃ is selected from a group consisting of hydrogen atom, halogen atom,nitro group, cyano group, sulfo group, amino group, carboxyl group,hydroxyl group, sulfydryl group, hydrocarbyl group, substitutedhydrocarbyl group, alkoxy group, substituted alkoxy group and acylgroup;

R₄ is selected from a group consisting of hydrogen atom, halogen atom,nitro group, cyano group, sulfo group, amino group, carboxyl group,hydroxyl group, sulfydryl group, hydrocarbyl group, substitutedhydrocarbyl group, alkoxy group, substituted alkoxy group and acylgroup;

R₅ is selected from a group consisting of hydrogen atom, halogen atom,nitro group, cyano group, sulfo group, amino group, carboxyl group,hydroxyl group, sulfydryl group, hydrocarbyl group, substitutedhydrocarbyl group, alkoxy group, substituted alkoxy group and acylgroup; and

wherein at least one of R₁, R₂, R₃, R₄ and R₅ is not hydrogen atom.

Optionally, only one of R₁, R₂, R₃, R₄ and R₅ is not hydrogen atom, andany one of the others is hydrogen atom.

Optionally, each one of R₂, R₃, R₄ and R₅ is hydrogen atom, and R₁ ishalogen atom or ethoxy group.

Optionally, each one of R₂, R₃, R₄ and R₅ is hydrogen atom, and R₁ isfluorine atom or bromine atom.

Optionally, each one of R₁, R₃, R₄ and R₅ is hydrogen atom, and R₂ isbromine atom, chlorine atom, fluorine atom or nitro group.

Optionally, each one of R₁, R₂, R₄ and R₅ is hydrogen atom, and R₃ ischlorine atom, methoxy group or nitro group.

In an embodiment, a pharmaceutical composition comprising any one of thebenfotiamine derivatives above or a salt thereof is provided.

Optionally, the pharmaceutical composition is used for preparing amedicine for preventing and treating Alzheimer's disease or aging.

Compared with the prior art, the present disclosure relates to a seriesof benfotiamine derivatives. Furthermore, in the present disclosure,when the ortho position of benzene ring is only a halogen atom, or anethoxy group substitution, or the meta position is only a bromine atom,a chlorine atom, a fluorine atom or a nitro group substitution, or thepara position is only a chlorine atom, a methoxy or a nitro groupsubstitution; its compound has significant inhibition effect on Aβ40 andAβ42. What is more, when the ortho position of benzene ring is only afluorine atom or a bromine atom substitution, the compound has anoutstanding inhibition effect on Aβ40 and Aβ42.

DETAILED DESCRIPTION

In an embodiment, benfotiamine derivatives are provided, wherein thebenfotiamine derivatives are as shown in formula (1):

wherein, R₁ is selected from a group consisting of hydrogen atom,halogen atom, nitro group, cyano group, sulfo group, amino group,carboxyl group, hydroxyl group, sulfydryl group, hydrocarbyl group,substituted hydrocarbyl group, alkoxy group, substituted alkoxy groupand acyl group;

R₂ is selected from a group consisting of hydrogen atom, halogen atom,nitro group, cyano group, sulfo group, amino group, carboxyl group,hydroxyl group, sulfydryl group, hydrocarbyl group, substitutedhydrocarbyl group, alkoxy group, substituted alkoxy group and acylgroup;

R₃ is selected from a group consisting of hydrogen atom, halogen atom,nitro group, cyano group, sulfo group, amino group, carboxyl group,hydroxyl group, sulfydryl group, hydrocarbyl group, substitutedhydrocarbyl group, alkoxy group, substituted alkoxy group and acylgroup;

R₄ is selected from a group consisting of hydrogen atom, halogen atom,nitro group, cyano group, sulfo group, amino group, carboxyl group,hydroxyl group, sulfydryl group, hydrocarbyl group, substitutedhydrocarbyl group, alkoxy group, substituted alkoxy group and acylgroup;

R₅ is selected from a group consisting of hydrogen atom, halogen atom,nitro group, cyano group, sulfo group, amino group, carboxyl group,hydroxyl group, sulfydryl group, hydrocarbyl group, substitutedhydrocarbyl group, alkoxy group, substituted alkoxy group and acylgroup; and

wherein at least one of R₁, R₂, R₃, R₄ and R₅ is not hydrogen atom.

In some embodiments, the hydrocarbyl group includes a straight chain,branched chain or cyclic hydrocarbyl group, and the hydrocarbyl groupmay be alkane base, may also be olefin base or acetylene base, butoptionally alkane base, more specifically, e.g. methyl, ethyl, vinyl,allyl, n-propyl, isopropyl, n-butyl, sec-butyl, tertiary butyl,isobutyl, amyl, 1-ethyl propyl, 1-methyl butyl, cyclopentyl, hexyl,1-methyl amyl, 1-ethyl butyl, cyclohexyl, 2-heptyl, heptyl, octyl,nonyl, decyl, undecyl, dodecyl, tridecyl, myristyl, pentadecyl,hexadecyl, heptadecyl, octadecyl, nonadecyl, aryl alkyl, eicosyl,heneicosyl, docosyl, tricosyl, phenyl, 2-methyl phenyl, 3-methyl phenyl,4-methyl phenyl, 1-naphthyl, 2-naphthyl, benzyl or 2-phenethyl, etc.

In some embodiments, the substituted hydrocarbyl group includes thehalogen atom substitution, nitro substitution, cyano substitution, sulfosubstitution, amine substitution, carboxyl substitution, hydroxylsubstitution or sulfydryl substitution, etc., such as methoxy ethyl,ethoxy ethyl, butoxy ethyl, trifluoromethyl, or pentafluoroethyl, etc.as described above.

In some embodiments, the alkoxy group includes a straight chain,branched chain or cyclic alkoxy, e.g. methoxy, ethoxy, n-propoxy,isopropoxy, n-butoxy, sec-butoxy, tert-butoxy, isobutoxy, pentyloxy,1-ethyl propoxy, 1-methyl butoxy, cyclic pentyloxy, hexyloxy, 1-methylpentyloxy, 1-ethyl butoxy, cyclic hexyloxy, 2-heptyloxy, heptyloxy,octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, tridecyloxy,tetradecyloxy, pentadecyloxy, hexadecyloxy, heptadecyloxy, octadecyloxy,nonadecyloxy, aryl alkyloxy, eicosyloxy, heneicosyloxy, docosyloxy,tricosyloxy, phenyloxy, 2-methyl phenyloxy, 3-methyl phenyloxy, 4-methylphenyloxy, 1-naphthyloxy, 2-naphthyloxy, benzyloxy or 2-phenethyloxy,etc.

In some embodiments, the substituted alkoxy group includes the halogenatom substitution, nitro substitution, cyano substitution, sulfosubstitution, amine substitution, carboxyl substitution, hydroxylsubstitution or sulfydryl substitution, etc., more specifically, e.g.methoxy ethyloxy, ethoxy ethyloxy, butoxy ethyloxy, trifluoromethyloxy,or pentafluoroethyloxy, etc.

In some embodiments, the acyl group includes a variety of alkyl acyl ora variety of substituted alkyl acyl, and the substituted acyl includesthe halogen atom substitution, nitro substitution, cyano substitution,sulfo substitution, amine substitution, carboxyl substitution, hydroxylsubstitution or sulfydryl substitution, etc., more specifically, e.g.formyl, acetyl, n-propionyl, sec-propionyl, n-butanoyl, sec-butyryl,t-butyryl, iso-butyryl, valeryl, 1-ethyl propionyl, 1-methyl butanoyl,cyclopentanoyl, hexanoyl, 1-methyl valeryl, 1-ethyl butanoyl,cyclohexanoyl, 2-heptanoyl, heptanoyl, octanoyl, nonanoyl, decanoyl,undecanoyl, dodecanoyl, tridecanoyl, tetradecanoyl, pentadecanoyl,hexadecanoyl, heptadecanoyl, octadecanoyl, nonadecanoyl, aryl alkenoyl,eicosanoyl, heneicosanoyl, docosanoyl, tricosanoyl, benzoyl, 2-methylbenzoyl, 3-methyl benzoyl, 4-methyl benzoyl, 1-naphthoyl, 2-naphthoyl,benzoyl, 2-phenylacetyl, methoxy ethanoyl, ethoxy acetyl, butoxy acetyl,trifluoroformyl or pentafluoroacetyl, etc.

Considering the inhibitory effect of the benfotiamine derivatives onAβ40 and Aβ42, optionally only one of R₁, R₂, R₃, R₄ and R₃ is nothydrogen atom, and any one of the others is hydrogen atom, furtheroptionally each one of R₂, R₃, R₄ and R₅ is hydrogen atom, and R₁ ishalogen atom or ethoxy group, or each one of R₁, R₃, R₄ and R₅ ishydrogen atom, and R₂ is bromine atom, chlorine atom, fluorine atom ornitro group, or each one of R₁, R₂, R₄ and R₅ is hydrogen atom, and R₃is chlorine atom, methoxy group or nitro group, and further optionallyeach one of R₂, R₃, R₄ and R₅ is hydrogen atom, and R₁ is fluorine atomor bromine atom.

In an embodiment, a method for preparing the above benfotiaminederivatives is provided, wherein a compound of monophosphothiamine theformula (1a) shows reacts with a compound of benzoyl chloride theformula (1b) shows so as to prepare and obtain the benfotiaminederivatives of the formula (1),

wherein,

R₁ is selected from a group consisting of hydrogen atom, halogen atom,nitro group, cyano group, sulfo group, amino group, carboxyl group,hydroxyl group, sulfydryl group, hydrocarbyl group, substitutedhydrocarbyl group, alkoxy group, substituted alkoxy group and acylgroup;

R₂ is selected from a group consisting of hydrogen atom, halogen atom,nitro group, cyano group, sulfo group, amino group, carboxyl group,hydroxyl group, sulfydryl group, hydrocarbyl group, substitutedhydrocarbyl group, alkoxy group, substituted alkoxy group and acylgroup:

R₃ is selected from a group consisting of hydrogen atom, halogen atom,nitro group, cyano group, sulfo group, amino group, carboxyl group,hydroxyl group, sulfydryl group, hydrocarbyl group, substitutedhydrocarbyl group, alkoxy group, substituted alkoxy group and acylgroup;

R₄ is selected from a group consisting of hydrogen atom, halogen atom,nitro group, cyano group, sulfo group, amino group, carboxyl group,hydroxyl group, sulfydryl group, hydrocarbyl group, substitutedhydrocarbyl group, alkoxy group, substituted alkoxy group and acylgroup;

R₅ is selected from a group consisting of hydrogen atom, halogen atom,nitro group, cyano group, sulfo group, amino group, carboxyl group,hydroxyl group, sulfydryl group, hydrocarbyl group, substitutedhydrocarbyl group, alkoxy group, substituted alkoxy group and acylgroup; and

wherein at least one of R₁, R₂, R₃, R₄ and R₃ is not hydrogen atom.

The method for preparing the benfotiamine derivatives according toembodiments of the present disclosure may be carried out by thereference to the existing method of preparing benfotiamine with thereaction of monophosphothiamine and benzoyl chloride. For example, theexperimental conditions disclosed in the patent application EP2918593A1,the monophosphothiamine shown in the formula (1a) is dissolved in water,cooled to 0-5° C., added with 30% sodium hydroxide solution, adjusted tohave the pH value between 11 and 12, and stirred for 1-2 hours. Underthe temperature for 0-5° C., the above solution is added with benzoylchloride shown in the formula (1b). The pH value is controlled andadjusted between 11 and 12 during above process. After finishing adding,tester needs to get the above solution to react for 1-3 hours under thetemperature for 5-10° C., then concentrated hydrochloric acid is addedto adjust the pH value to between 3 and 4, stirring and filtering areperformed with adding ethyl acetate, and the filter cake is dried toobtain the product.

In some embodiments, the method for preparing the benfotiaminederivatives is limited to R₁, R₂, R₃, R₄ and R₅ as described above.

Further, the present disclosure also provides a pharmaceuticalcomposition comprising the benfotiamine derivatives or a salt thereof,optionally the pharmaceutical composition is used to prepare apharmaceutical composition for the prevention and treatment ofAlzheimer's disease or aging. The salt is medically acceptable salt,such as lithium salt, sodium salt, potassium salt or calcium salt, etc.The composition may be made into tablets, powders, aerosols,water-injection, powder-injection, rectal suppositories or skin patches(transdermal administration) according to the conventional method.

EXAMPLES

Measurement of the Present Disclosure

Nuclear magnetic (¹H NMR): NMR displacement (δ) is given in units of10⁻⁶ (ppm). NMR spectra are obtained using a Bruker AVANCE-500 nuclearmagnetometer using deuterated dimethyl sulfoxide (DMSO-d₆), deuteratedmethanol (CD₃OD) or deuterated water (D₂O) as a solvent andtetramethylsilane (TMS) as the internal standard.

Mass spectrometry (MS): Determination of MS by Agilent (ESI) massspectrometer (producer: Agilent, Model: Agilent 6110).

1. Bioassays

Materials and Methods

(1) BCA protein concentration assay kit is purchased from Beyotime, Aβ40and AB42 test kits are purchased from Wako Company. Except the fetalbovine serum (FBS) is purchased from Shanghai Pulong BiotechnologyResearch and Development Co. Ltd., the other related reagents arepurchased from Gibico Company.

(2) HEK293APP/sw overexpression cell culture: cells are cultured in 48microwell plate with DMEM culture solution (including 10% FBS, 100 μg/mLG418 (Geneticin) and penicillin and streptomycin), and a 4 mM stock inDMEM is diluted with DMEM to 400 μM and added to cell culture medium by500 μL/well at 70% cell density and treated for 24 h.

(3) After the supernatant of culture solution is added to the BCAreagent at room temperature for 30 minutes, the absorption value of eachwell is measured at the OD 570 nm by the microplate reader and the totalprotein concentration is calculated according to the protein standardcurve. Meanwhile, the concentration of Aβ40 and Aβ42 in the supernatantof culture solution is measured. Briefly, the supernatant is added tothe 96 microwell plate coated by primary antibodies and incubated at 4°C. for overnight. Then the solution in the 96 microwell plate is removedand washed, and HRP (horseradish oxide enzyme) marked antibody is addedto the solution and incubated at 4° C. for 2 hours. The antibody isremoved and the plate is washed. After TMB substrate is added to eachwell at room temperature for 30 minutes, and the stop buffer is added toeach well. The absorption value of each well is measured at the OD 450nm by the microplate reader and the concentrations of Aβ40 and Aβ42 arecalculated according to the standard curves of Aβ40 and Aβ42respectively, and the final concentration is obtained by adjusting theconcentrations of Aβ40 and Aβ42 according to the total proteinconcentration.

Example 1

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)3-methoxybenzothioate1-1 is synthesized:

The monophosphothiamine (38 g, 0.09 mol) is dissolved in water (103 g,5.7 mol), and cooled to 0-5° C. 30% sodium hydroxide solution (87.3 g,0.65 mol) is added to the solution cooled, adjusted with the pH between11 and 12, and stirred for 1.5 hours. After that, the 3-methoxybenzoylchloride (20.4 g, 0.12 mol) is added to the above solution at 0-5° C.,and controlled to regulate the pH value between 11 and 12 during theprocess. Then, it is reacted for 2 hours at 5-10° C. Thereafter,concentrated hydrochloric acid (34 g, 0.33 mol) is added to the solutionreacted to adjust the pH between 3 and 4, then 50 mL ethyl acetate isadded to the above solution and stirred for 16 hours. The solutionstirred is filtered to obtain a cake and the cake is dried to obtainproduct 1-1 (11 g, off-white solids).

The results of the product 1-1 measured by nuclear magnetic (¹H NMR) andmass spectrometry (MS) are shown as follows. The results of bioassays ofthe stock prepared with product 1-1 are shown in table 1.

MS m/z (ESI): 497.1 [M+H]⁺

¹H NMR (DMSO-d₆) δ 7.85 (d, 1H), 7.78 (d, 1H), 7.40 (t, 1H), 7.30 (d,1H), 7.25 (d, 1H), 7.13 (d, 1H), 4.45-4.25 (m, 2H), 3.88-3.75 (m, 5H),2.75-2.65 (m, 2H), 2.25 (s, 3H), 2.15 (s, 3H).

Example 2

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)4-ethoxybenzothioate1-2 is synthesized:

In the example, the synthetic route of example 1 is employed, thereactant of 3-methoxybenzoyl chloride is replaced with 4-ethoxybenzoylchloride, and product 1-2 (1.1 g, off-white solids) is obtained.

The results of the product 1-2 measured by nuclear magnetic (¹H NMR) andmass spectrometry (MS) are shown as follows. The results of bioassays ofthe stock prepared with product 1-2 are shown in table 1.

MS m/z (ESI): 511.1 [M+H]⁺

¹H NMR (DMSO-d₆) δ 7.85 (d, 1H), 7.78 (d, 1H), 7.65 (d, 2H), 7.00 (d,2H), 4.50-4.35 (m, 2H), 4.20-4.15 (m, 2H), 3.80-3.70 (m, 2H), 2.75-2.65(m, 2H), 2.25 (s, 3H), 2.15 (s, 3H), 1.30 (t, 3H).

Example 3

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)4-hydroxybenzothioate1-3 is synthesized:

In the example, the synthetic route of example 1 is employed, thereactant of 3-methoxybenzoyl chloride is replaced with 4-hydroxybenzoylchloride, and product 1-3 (0.2 g, off-white solids) is obtained.

The results of the product 1-3 measured by nuclear magnetic (¹H NMR) andmass spectrometry (MS) are shown as follows. The results of bioassays ofthe stock prepared with product 1-3 are shown in table 1.

MS m/z (ESI): 483.1 [M+H]⁺

¹H NMR (DMSO-d₆) δ 7.90 (s, 1H), 7.85 (s, 1H), 7.61 (d, 2H), 6.85 (d,2H), 4.53-4.31 (m, 2H), 3.87-3.78 (m, 2H), 2.76-2.64 (m, 2H), 2.30 (s,3H), 2.17 (s, 3H).

Example 4

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)2,6-difluorobenzothioate1-4 is synthesized:

In the example, the synthetic route of example 1 is employed, thereactant of 3-methoxybenzoyl chloride is replaced with 2, 6-difluorobenzoyl chloride, and product 1-4 (2.2 g, off-white solids) is obtained.

The results of the product 1-4 measured by nuclear magnetic (¹H NMR) andmass spectrometry (MS) are shown as follows. The results of bioassays ofthe stock prepared with product 1-4 are shown in table 1.

MS m/z (ESI): 503.0 [M+H]⁺

¹H NMR (DMSO-d₆) δ 7.85 (d, 2H), 7.65 (d, 1H), 7.25 (d, 2H), 4.65-4.35(m, 2H), 3.80-3.70 (m, 2H), 2.75-2.65 (m, 2H), 2.25 (s, 3H), 2.15 (s,3H).

Example 5

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)3-bromobenzothioate1-5 is synthesized:

In the example, the synthetic route of example 1 is employed, thereactant 3-methoxybenzoyl chloride is replaced with 3-bromobenzoylchloride, and product 1-5 (1.7 g, off-white solids) is obtained.

The results of the product 1-5 measured by nuclear magnetic (¹H NMR) andmass spectrometry (MS) are shown as follows. The results of bioassays ofthe stock prepared with product 1-5 are shown in table 1.

MS m/z (ESI): 545.0 [M+H]⁺

¹H NMR (DMSO-d₆) δ 7.93-7.89 (m, 3H), 7.76-7.72 (d, 2H), 7.48 (d, 1H),4.65-4.35 (m, 2H), 3.87 (d, 2H), 2.70 (d, 2H), 2.28 (s, 3H), 2.20 (s,3H).

Example 6

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)3-nitrobenzothioate1-6 is synthesized:

In the example, the synthetic route of example 1 is employed, thereactant of 3-methoxybenzoyl chloride is replaced with 3-nitrobenzoylchloride, and product 1-6 (0.2 g, off-white solids) is obtained.

The results of the product 1-6 measured by nuclear magnetic (¹H NMR) andmass spectrometry (MS) are shown as follows. The results of bioassays ofthe stock prepared with product 1-6 are shown in table 1.

MS m/z (ESI): 512.2 [M+H]⁺

¹H NMR (DMSO-d₆) δ 8.50 (d, 1H), 8.35 (d, 1H), 8.15 (d, 1H), 7.90 (d,1H), 7.87 (d, 1H), 7.75 (t, 1H), 4.50-4.35 (m, 2H), 3.87-3.75 (d, 2H),2.70 (d, 2H), 2.20 (s, 6H).

Example 7

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)4-fluorobenzothioate1-7 is synthesized:

In the example, the synthetic route of example 1 is employed, thereactant of 3-methoxybenzoyl chloride is replaced with 4-fluorobenzoylchloride, and product 1-7 (11 g, off-white solids) is obtained.

The results of the product 1-7 measured by nuclear magnetic (¹H NMR) andmass spectrometry (MS) are shown as follows. The results of bioassays ofthe stock prepared with product 1-7 are shown in table 1.

MS m/z (ESI): 485.1 [M+H]⁺

¹H NMR (DMSO-d₆) δ 7.93 (s, 1H), 7.90 (s, 1H), 7.79 (d, 2H), 7.40 (d,2H), 4.54-4.37 (m, 2H), 3.86 (d, 2H), 2.70 (d, 2H), 2.25 (s, 3H), 2.20(s, 3H).

Example 8

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)3-fluorobenzothioate1-8 is synthesized:

In the example, the synthetic route of example 1 is employed, thereactant of 3-methoxybenzoyl chloride is replaced with 3-fluorobenzoylchloride, and product 1-8 (11 g, off-white solids) is obtained.

The results of the product 1-8 measured by nuclear magnetic (¹H NMR) andmass spectrometry (MS) are shown as follows. The results of bioassays ofthe stock prepared with product 1-8 are shown in table 1.

MS m/z (ESI): 485.1 [M+H]⁺

¹H NMR (DMSO-d₆) δ 7.88 (s, 1H), 7.84 (s, 1H), 7.58 (d, 3H), 7.41 (d,1H), 4.51-4.35 (m, 2H), 3.84 (d, 2H), 2.71 (d, 2H), 2.23 (s, 3H), 2.19(s, 3H).

Example 9

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)2-fluorobenzothioate1-9 is synthesized:

In the example, the synthetic route of example 1 is employed, thereactant of 3-methoxybenzoyl chloride is replaced with 2-fluorobenzoylchloride, and product 1-9 (11 g. off-white solids) is obtained.

The results of the product 1-9 measured by nuclear magnetic (¹H NMR) andmass spectrometry (MS) are shown as follows. The results of bioassays ofthe stock prepared with product 1-9 are shown in table 1.

MS m/z (ESI): 485.1 [M+H]⁺

¹H NMR (DMSO-d₆) δ 7.94 (s, 1H), 7.89 (s, 1H), 7.67 (d, 2H), 7.37 (d,2H), 4.55-4.36 (m, 2H), 3.85 (d, 2H), 2.71 (d, 2H), 2.26 (s, 3H), 2.20(s, 3H).

Example 10

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)2-methylbenzothioate1-10 is synthesized:

In the example, the synthetic route of example 1 is employed, thereactant of 3-methoxybenzoyl chloride is replaced with 2-methylbenzoylchloride, and product 1-10 (11 g. off-white solids) is obtained.

The results of the product 1-10 measured by nuclear magnetic (¹H NMR)and mass spectrometry (MS) are shown as follows. The results ofbioassays of the stock prepared with product 1-10 are shown in table 1.

MS m/z (ESI): 481.1 [M+H]⁺

¹H NMR (DMSO-d₆) δ 7.89 (s, 1H), 7.87 (s, 1H), 7.56 (d, 1H), 7.48 (d,1H), 7.33 (d, 2H), 4.55-4.36 (m, 2H), 3.85 (d, 2H), 2.78 (d, 2H), 2.31(s, 3H), 2.27 (s, 3H), 2.19 (s, 3H).

Example 11

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)4-nitrobenzothioate1-11 is synthesized:

In the example, the synthetic route of example 1 is employed, thereactant of 3-methoxybenzoyl chloride is replaced with 4-nitrobenzoylchloride, and product 1-11 (10 g, off-white solids) is obtained.

The results of the product 1-11 measured by nuclear magnetic (¹H NMR)and mass spectrometry (MS) are shown as follows. The results ofbioassays of the stock prepared with product 1-11 are shown in table 1.

MS m/z (ESI): 512.2 [M+H]⁺

¹H NMR (DMSO-d₆) δ 8.35 (s, 1H), 8.33 (s, 1H), 7.94 (d, 1H), 7.92 (d,2H), 7.87 (s, 1H), 4.56-4.34 (m, 2H), 3.89-3.75 (m, 2H), 2.74 (d, 2H),2.21 (s, 6H).

Example 12

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)4-methoxybenzothioate1-12 is synthesized:

In the example, the synthetic route of example 1 is employed, thereactant of 3-methoxybenzoyl chloride is replaced with 4-methoxybenzoylchloride, and product 1-12 (10 g, off-white solids) is obtained.

The results of the product 1-12 measured by nuclear magnetic (¹H NMR)and mass spectrometry (MS) are shown as follows. The results ofbioassays of the stock prepared with product 1-12 are shown in table 1.

52 MS m/z (ESI): 497.1 [M+H]⁺

¹H NMR (DMSO-d₆) δ 7.91 (s, 1H), 7.85 (s, 1H), 7.71 (d, 2H), 7.06 (d,2H), 4.56-4.34 (m, 2H), 3.87-3.75 (m, 5H), 2.70 (s, 2H), 2.30 (s, 3H),2.18 (s, 3H).

Example 13

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)3-chlorobenzothioate1-13 is synthesized:

In the example, the synthetic route of example 1 is employed, thereactant of 3-methoxybenzoyl chloride is replaced with 3-chlorobenzoylchloride, and product 1-13 (10 g, off-white solids) is obtained.

The results of the product 1-13 measured by nuclear magnetic (¹H NMR)and mass spectrometry (MS) are shown as follows. The results ofbioassays of the stock prepared with product 1-13 are shown in table 1.

MS m/z (ESI): 501.1 [M+H]⁺

¹H NMR (DMSO-d₆) δ 7.91 (s, 2H), 7.78 (d, 1H), 7.69 (d, 1H), 7.63 (s,1H), 7.57 (d, 1H), 7.45-7.20 (m, 2H), 4.53-4.35 (m, 2H), 3.87-3.75 (m,2H), 2.71 (d, 2H), 2.25 (s, 3H), 2.20 (s, 3H).

Example 14

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)3-methylbenzothioate1-14 is synthesized:

In the example, the synthetic route of example 1 is employed, thereactant of 3-methoxybenzoyl chloride is replaced with 3-methylbenzoylchloride, and product 1-14 (11 g, off-white solids) is obtained.

The results of the product 1-14 measured by nuclear magnetic (¹H NMR)and mass spectrometry (MS) are shown as follows. The results ofbioassays of the stock prepared with product 1-14 are shown in table 1.

MS m/z (ESI): 481.1 [M+H]⁺

¹H NMR (DMSO-d₆) δ 7.90 (s, 1H), 7.87 (s, 1H), 7.52-7.49 (m, 3H), 7.43(d, 1H), 4.55-4.36 (m, 2H), 3.86 (d, 2H), 2.71 (s, 2H), 2.38 (s, 3H),2.28 (s, 3H), 2.18 (s, 3H).

Example 15

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)4-chlorobenzothioate1-15 is synthesized:

In the example, the synthetic route of example 1 is employed, thereactant of 3-methoxybenzoyl chloride is replaced with 4-chlorobenzoylchloride, and product 1-15 (0.3 g, off-white solids) is obtained.

The results of the product 1-15 measured by nuclear magnetic (¹H NMR)and mass spectrometry (MS) are shown as follows. The results ofbioassays of the stock prepared with product 1-15 are shown in table 1.

MS m/z (ESI): 501.0 [M+H]⁺

¹H NMR (DMSO-d₆) δ 7.88 (s, 1H), 7.84 (s, 1H), 7.71 (d, 2H), 7.61 (d,2H), 4.50-4.35 (m, 2H), 3.87 (d, 2H), 2.71 (d, 2H), 2.22 (s, 3H), 2.19(s, 3H).

Example 16

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)3-ethoxybenzothioate1-16 is synthesized:

In the example, the synthetic route of example 1 is employed, thereactant of 3-methoxybenzoyl chloride is replaced with 2-ethoxybenzoylchloride, and product 1-16 (0.2 g, off-white solids) is obtained.

The results of the product 1-16 measured by nuclear magnetic (¹H NMR)and mass spectrometry (MS) are shown as follows. The results ofbioassays of the stock prepared with product 1-16 are shown in table 1.

MS m/z (ESI): 511.1 [M+H]⁺

¹H NMR (DMSO-d₆) δ 8.06 (s, 1H), 7.92 (s, 1H), 7.56 (d, 2H), 7.17 (d,1H), 7.03 (t, 1H), 4.58-4.38 (m, 2H), 4.18 (q, 2H), 3.93-3.80 (m, 2H),2.68 (s, 2H), 2.19 (s, 6H), 1.35 (t, 3H).

Example 17

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)4-bromobenzothioate1-17 is synthesized:

In the example, the synthetic route of example 1 is employed, thereactant of 3-methoxybenzoyl chloride is replaced with 4-bromobenzoylchloride, and product 1-17 (3.5 g, off-white solids) is obtained.

The results of the product 1-17 measured by nuclear magnetic (¹H NMR)and mass spectrometry (MS) are shown as follows. The results ofbioassays of the stock prepared with product 1-17 are shown in table 1.

MS m/z (ESI): 547.0 [M+H]⁺

¹H NMR (DMSO-d₆) δ 8.08 (d, 1H), 7.90 (s, 1H), 7.86 (d, 1H), 7.76 (d,1H), 7.73 (d, 11H), 7.63 (d, 1H), 4.50-4.35 (m, 2H), 3.87-3.75 (m, 2H),2.70 (t, 2H), 2.24 (s, 3H), 2.19 (s, 3H).

Example 18

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)2-bromobenzothioate1-18 is synthesized:

In the example, the synthetic route of example 1 is employed, thereactant of 3-methoxybenzoyl chloride is replaced with 2-bromobenzoylchloride, and product 1-18 (3.5 g, off-white solids) is obtained.

The results of the product 1-18 measured by nuclear magnetic (¹H NMR)and mass spectrometry (MS) are shown as follows. The results ofbioassays of the stock prepared with product 1-18 are shown in table 1.

MS m/z (ESI): 593.0 [M+H]⁺

¹H NMR (DMSO-d₆) δ 7.98-7.93 (m, 3H), 7.51 (t, 1H), 7.42 (d, 1H), 7.32(d, 1H), 4.64-4.32 (m, 2H), 3.87-3.75 (m, 2H), 2.78 (s, 2H), 2.20 (s,3H), 2.30 (s, 3H).

Example 19

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)2-iodobenzothioate1-19 is synthesized:

In the example, the synthetic route of example 1 is employed, thereactant of 3-methoxybenzoyl chloride is replaced with 2-iodobenzoylchloride, and product 1-19 (0.06 g, off-white solids) is obtained.

The results of the product 1-19 measured by nuclear magnetic (¹H NMR)and mass spectrometry (MS) are shown as follows. The results ofbioassays of the stock prepared with product 1-19 are shown in table 1.

MS m/z (ESI): 547.0 [M+H]⁺

¹H NMR (DMSO-d₆) δ 7.96 (s, 1H), 7.93 (s, 1H), 7.74 (s, 1H), 7.50 (s,3H), 4.60-4.35 (m, 2H), 3.87-3.75 (m, 2H), 2.70 (d, 2H), 2.31 (s, 3H),2.20 (s, 3H).

Example 20

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)3-vinylbenzothioate1-20 is synthesized:

In the example, the synthetic route of example 1 is employed, thereactant of 3-methoxybenzoyl chloride is replaced with 3-ethenylbenzoylchloride, and product 1-20 (0.8 g, off-white solids) is obtained.

The results of the product 1-20 measured by nuclear magnetic (¹H NMR)and mass spectrometry (MS) are shown as follows. The results ofbioassays of the stock prepared with product 1-20 are shown in table 1.

MS m/z (ESI): 492.12 [M+H]⁺

¹H NMR (DMSO-d₆) δ 7.93 (s, 1H), 7.89 (s, 1H), 7.83 (d, 1H), 7.72 (s,1H), 7.63 (d, 1H), 7.53 (t, 1H), 6.80 (q, 1H), 5.93 (d, 1H), 5.38 (d,1H), 4.48 (br, 2H), 3.87 (d, 2H), 2.72 (s, 2H), 2.27 (s, 3H), 2.20 (s,3H).

Example 21

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)4-vinylbenzothioate1-21 is synthesized:

In the example, the synthetic route of example 1 is employed, thereactant of 3-methoxybenzoyl chloride is replaced with 4-ethenylbenzoylchloride, and product 1-21 (2 g, off-white solids) is obtained.

The results of the product 1-21 measured by nuclear magnetic (¹H NMR)and mass spectrometry (MS) are shown as follows. The results ofbioassays of the stock prepared with product 1-21 are shown in table 1.

MS m/z (ESI): 492.12 [M+H]⁺

¹H NMR (DMSO-d₆) δ 7.88-7.87 (m, 2H), 7.70 (d, 2H), 7.62 (d, 2H), 7.13(br, 2H), 6.85 (q, 1H), 6.04 (d, 1H), 5.45 (d, 1H), 4.43 (br, 2H), 3.82(d, 2H), 2.71 (s, 2H), 2.23 (s, 3H), 2.18 (s, 3H).

Example 22

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)2-nitrobenzothioate1-22 is synthesized:

In the example, the synthetic route of example 1 is employed, thereactant of 3-methoxybenzoyl chloride is replaced with 2-nitrobenzoylchloride, and product 1-22 (50 mg, off-white solids) is obtained.

The results of the product 1-22 measured by nuclear magnetic (¹H NMR)and mass spectrometry (MS) are shown as follows. The results ofbioassays of the stock prepared with product 1-22 are shown in table 1.

MS m/z (ESI): 512.2 [M+H]⁺

¹H NMR (DMSO-d₆) δ 8.12 (d, 1H), 7.93 (s, 1H), 7.92 (s, 1H), 7.87-7.83(m, 2H), 7.63 (d, 1H), 7.29 (br, 1H), 4.49 (br, 2H), 3.89 (d, 2H), 2.74(s, 2H), 2.25 (s, 3H), 2.20 (s, 3H).

Example 23

(Z)—S-(2-(N-((4-amino-2-methylpyrimidin-5-yl)methyl)formamido)-5-(phosphonooxy)pent-2-en-3-yl)2,6-dimethylbenzothioate1-23 is synthesized:

In the example, the synthetic route of example 1 is employed, thereactant of 3-methoxybenzoyl chloride is replaced with2,6-dimethylbenzoyl chloride, and product 1-23 (18 mg, off-white solids)is obtained.

The results of the product 1-23 measured by nuclear magnetic (¹H NMR)and mass spectrometry (MS) are shown as follows. The results ofbioassays of the stock prepared with product 1-23 are shown in table 1.

MS m/z (ESI): 495.1 [M+H]⁺

¹H NMR (DMSO-d₆) δ 7.97 (d, 2H), 7.26 (s, 1H), 7.08 (s, 2H), 4.85 (br,2H), 3.86 (s, 2H), 2.76 (s, 2H), 2.32 (s, 3H), 2.19 (s, 3H).

Comparative Example 1

Bioassay is carried out without the stock and a medium as a control, theresults of which are shown in table 1.

Comparative Example 2

The results of bioassay of the stock prepared with benfotiamine areshown in table 1.

Table 1 shows the content of Aβ40 and Aβ42 protein secreted by APP/293cells after treatment of benfotiamine derivatives.

TABLE 1 Aβ42 Aβ40 Aβ42 Aβ40 content content content content Compound(pmol/L) (pmol/L) Compound (pmol/L) (pmol/L) Example 1 12.14 135.09Example 2 7.19 93.07 Example 3 10.79 121.48 Example 4 8.86 133.25Example 5 6.77 25.65 Example 6 3.31 81.05 Example 7 13.08 152.06 Example8 8.35 87.33 Example 9 2.01 15.00 Example 10 9.78 112.32 Example 11 5.2160.98 Example 12 3.92 41.60 Example 13 6.37 69.35 Example 14 6.41 97.97Example 15 7.16 60.27 Example 16 5.93 42.76 Example 17 8.89 112.53Example 18 2.60 21.19 Example 19 5.50 62.74 Example 20 10.33 117.16Example 21 11.24 127.41 Example 22 11.31 127.81 Example 12.64 143.18Comparative 11.08 127.81 23 Example 1 Comparative 5.04 53.77 Example 2

Although the present disclosure has been described above, the presentdisclosure is not limited thereto. It should be understood by thoseskilled in the art that various changes and modifications may be madewithout departing from the spirit and scope of the disclosure, andtherefore, the scope of the disclosure should be limited by the scope ofthe claims.

1-20. (canceled)
 21. A benfotiamine derivative represented by formula(1)

wherein each one of R₂, R₃, R₄ and R₅ is hydrogen atom, and R₁ isfluorine atom, bromine atom or alkoxy group; or each one of R₁, R₃, R₄and R₅ is hydrogen atom, and R₂ is fluorine atom, bromine atom or nitrogroup.
 22. (canceled)
 23. The benfotiamine derivative according to claim21, wherein each one of R₂, R₃, R₄ and R₅ is hydrogen atom, and R₁ isethoxy group.
 24. (canceled)
 25. The benfotiamine derivative accordingto claim 21, wherein each one of R₁, R₃, R₄ and R₅ is hydrogen atom, andR₂ is bromine atom.
 26. A method for producing the benfotiaminederivative according to claim 21, comprising reacting a compound ofmonophosphothiamine shown in formula (1a) with a compound of benzoylchloride shown in formula (1b),

wherein, each one of R₂, R₃, R₄ and R₅ is hydrogen atom, and R₁ isfluorine atom, bromine atom or alkoxy group; or each one of R₁, R₃, R₄and R₅ is hydrogen atom, and R₂ is fluorine atom, bromine atom or nitrogroup.
 27. A method of treating Alzheimer's disease, comprisingadministering the benfotiamine derivative according to claim 21 to asubject in need thereof.